The MOPAR hard trifold cover is water tight and works well. Excellent quality. The cheap covers leak either immediately or after the second winter. The expensive ones also leak badly, soaking whatever is in the bed. You would think if you spend a lot of cash on a name brand one that they should be good quality, but it turns out to be mostly marketing. I would never buy another BAK because it leaked and fell apart with routine/daily use after about 2 years. They sent me more seals and fasteners but it just leaked at the seams, eventually they gave up. Very disappointed in the product.
Now if you don't care much about leakage and fit, and plan to replace them every three years or so, just about any cover will do.